Treatment of hydrocarbon oils



. 26, 1939. v. STAPLETON TREATMENT OF HYDROCARBON OILS Filed Nov. 15, 1933 INVENTOR VICTOR STAPLETON.

ATTORNEY UNITE snrss TREATMENT OF HYDROCARBON OILS Victor Stapleton, Port Arthur, Tex., assignor to The Texas Company, New York, N. Y., a corporation of Delaware Application November 15, 1933, Serial No. 698,132

1 Claim. (Cl. 196-58) This invention relates to the treatment of hyboiling charging stock such as reduced crude is drocarbon oils and has special reference to the used, a portion of the charging oil from line 23 cracking of hydrocarbon oils in which a clean may be introduced into the bottom portion of condensate stock is subjected to vapor phase the reaction and separating chamber E2 to flush 5 cracking treatment and a less clean stock such out the bottom of the chamber and prevent the 5 as reduced crude or a dirty gas oil is, subjected deposition of coke therein. It has been found to liquid phase cracking treatment. to be particularly advantageous to introduce a One of the primary objects of theinventicn is small amount of an extremely high boiling point to more'efiectively utilize the contained heat of oil into chamber l2 adjacent the outlet line 32 p the products resulting from the vapor phase to maintain conditions of liquidity in the irn- 10 cracking treatment for carrying out the liquid mediate proximity of the outlet. In most inphase cracking treatment. stances it is desirable to introduce the larger pro- A further object of the invention is to provide portion of the oil into the upper zone of the liquid a method involving a combined vapor phase. and phase cracking chamber it and to periodically 5 liquid phase cracking treatment in which only introduce a portion of this oil into the bottom of 115 clean condensate stock is subjected to high temthe digestion chamber l2. In some instances,

perature conditions within a tubular heating coil particularly when rather low boiling hydrocar-- and in which the clean condensate stock is heated bons are being utilized as charging stock it may to'a temperature sufficient to carry out, not only be desirable to continuously or periodically inthe vapor phase cracking of the products'within troduce a high boiling residual oil into the botthe coil, but also the liquid phase cracking of tom of chamber it from an extraneous source other hydrocarbons which are not passed through through line 35 in order to maintain the desired the tubular heating coil, liquid conditions adjacent the outlet.

Other objects of the invention will be apparent It may also e esir to in ro fr h h e from the more detailed description. ing oil into the vapor transfer line ill for quench For a clearer understanding of the invention g hot Vapor products fIOm e heating o l reference is now made to the accompanying The fresh Oil introduced into the pp p drawing which is a schematic illustration of a tion of diges ion chamber I3 is caused to cascade type of apparatus suitable for carrying out the Over a plurality of heme plates 25 located in the invention. upper portion of the chamber it in a downward In the drawing the numeral Ill designates a direction counter-current to the flow of hot furnace setting having a heating coil ll mounted porous products from the vapor phase digestion therein. The apparatus further includes a rechamber l2. The fresh oil coming in contact action and separating chamber l2, a liquid phase with the hot vapors is heated to a temperature cracking and scrubbing chamber it, a fractionatsufficient to effect conversion of heavier hydroing chamber M and other adjunctive elements carbons into lighter hydrocarbons. A considforming a part of conventional oil cracking aperable volume of liquid is maintained within the paratus such as a reflux exchanger l5, gasoline chamber l3 so as to allow a digestion period to condenser l6, accumulator tank it for receiving effect the desired conversion. Lighter constituthe gasoline fraction, transfer lines for liquid and ents, including, as oil which may be contained 40 vapor products et cetera. within the original charging stock, are vaporized In accordance with the invention the oil to be within the chamber l3. 7 7 treated, such as, for example, reduced crude or Uncondensed vapors, formed in chamber it a dirty gas oil, is introduced into the system as a result of the conversion treatment the.

through line !8 provided with a pump l9 for stripping of the original oil, together with the un- 45 maintaining the oil under suitable head of prescondensed vapor products from the vapor phase sure. 7 digestion chamber I2 are scrubbed by the fresh If desired the fresh oil may be passed through oil introduced into the upper portion of the a coil 20 in the reflux exchanger l5 and utilized chamber l3 and the clean vapors are removed for cooling the vapors issuing from the fractionfrom the chamber through the line 26 and intro- 50 ating chamber M or the coil 211 may be by-passed duced into the bottom portion of the fractionby a line 2! provided with valve 22 and the fresh ating chamber l4. 7 H oil conducted through line 23 into the upper zone The chamber M is provided with suitable fracof the liquid phase cracking chamber l3. tionating elements 2'! which cool and fractionate If desired, particularly in cases Where a high the vapors. The uncondensed vapors from 55 chamber 14 are passed through the reflux exchanger l5 wherein the vapors are subjected to a further cooling after which they are passed through line 28 to condenser IS in which the desired gasoline fraction is condensed. The gasoline fraction having the desired end point is thereafter collected in the accumulator tank [1.

The condensate formed in the fractionating chamber 4 is withdrawn from the bottom thereof through line 29 provided with a hot oil pump 30 by which the condensate is forced throughthe tubular heating coil H. The oil passing through the heating coil II is brought to a temperature sufficient to effect rapid conversion of the hydrocarbons. For example, the conditions maintained within the cracking coil may be such as to effect from 15-25% conversion per pass. The hot vapor products are removed from the heating coil ll through line 3| and introduced into the upper portion of the reaction and separating chamber I2.

The heavier liquid products resulting from th conversion and digestion are removed from the chamber [2 through line 32 at a rate suflicient to prevent any substantial accumulation of liquid Within the chamber. The residual liquids withdrawn from chambers l2 and I3 are preferably passed to suitable tar stripping apparatus (not shown) for removing lighter constituents therefrom.

While only one reaction and separating chamber has been shown for purposes of illustration, it is understood that any suitable number may be provided, arranged either in parallel or in series, in which cases the liquid is withdrawn from the bottom of each of the chambers at a rate sufficient to prevent substantial accumulation of liquid therein and the withdrawn liquid is passed to the tar stripping equipment as hereinbefore pointed out.

The vaporous products, after being digested in the chamber l2 for a desired period are introduced into a body of hydrocarbon oil in the liquid phase cracking chamber i 3 through transfer line 33 provided with a reducing valve 3d. The pressure within the liquid phase cracking chamber l3 may be maintained lower than that existing in chamber I2. As an example, chamber it may be maintained at a pressure ranging from 300-500 pounds a square inch and the chamber l3 maintained at a pressure ranging from to 200 pounds per square inch. It is understood that this example is merely for purposes of illustration and that other suitable pressure conditions may be maintained as desired.

The hot vapor products introduced into the chamber 13 serve to maintain the body of oil contained therein, at a cracking temperature so as to convert heavier hydrocarbons contained in the charging oil into lighter hydrocarbons as well as to strip the lighter constituents from the fresh charge.

As an example of the temperature conditionswhich are suitable for carrying out the invention the fresh oil may be heated in the preheater I 5 to a temperature approximately 500 F. after which it is introduced into the cracking chamber l3 where it is raised to a temperature ranging from 750850 F. by the hot vapor products from the reaction chamber l2. The condensate, in passing through the heating coil ll, may be brought to a temperature ranging from 900-1000 F. and the cracking chamber l2 maintained at a temperature above 850 F. and preferably of the order of 875 F.-950 F. It will be clear, however, that the temperature conditions will depend upon a number of factors and may vary within quite wide limits without in any way modifying or changing the invention.

As hereinbefore mentioned, the hot vapor products in chamber I3 are subjected to a scrubbing by the fresh oil being introduced into the upper portion of the chamber l3 so that all entrained coke and heavy residual matter may be removed from the vapors before being passed into the'fractionating chamber and consequently a clean condensate is produced in the chamber I4.

While the preferred embodiment has been described for purposes of illustration it is understood that the invention embraces such other modifications and variations as come within the scope and spirit thereof, and the invention is not to be limited except as necessary to distinguish from prior art.

What I claim is:

In the conversion of higher boiling hydrocarbon oils into lower boiling ones, the process that comprises heating a confined stream of condensate oil to a cracking temperature of upwards of 900 F. to effect a high rate of cracking per pass, directing the stream of cracked products into an enlarged cracking chamber wherein separation of vapors from liquid takes place, maintaining a cracking temperature of upwards of 850 F., under superatmospheric pressure in the enlarged cracking chamber, separately with-' drawing liquid from the enlarged cracking chamber at a rate adequate to prevent the accumulation of liquid therein, passing the separated vapors without further heating directly into a second cracking chamber below the liquid level therein, introducing fresh charging stock for the process into the system, directing the greater part thereof into a dephlegmating zone in the second cracking chamber above the liquid level therein whereby the stock thus introduced flows countercurrent to the rising vapors separated therein and dephlegmates the separated vapors before reaching the body of liquid oil, maintaining a large body of liquid oil therein at a ber and subjecting them to fractionation to separate out a condensate and conducting said condensate to aforesaid confined stream.

VICTOR STAPLETON; 

